Historically, self-contained receptacles have been deployed in pre-manufactured and mobile housing, structures in which placement of electrical outlets can be constrained by spatial limitations. However, more recently their use has been expanded to include traditional housing as well as commercial buildings and churches. Self-contained receptacles facilitate the use of electronic accessories in areas such as window sills, mantles, countertops, and floors without the use of unsightly and potentially hazardous extension cords.
In many applications, self-contained receptacles are configured in a “daisy chain” arrangement in which power enters the receptacle, provides power to the receptacle, and then exits the receptacle to provide power for a separate device. In general, prior art receptacles operated in this manner require that a single power cord enter the receptacle, electrically connect to the receptacle through an insulation displacement connection, then exit the receptacle. Oftentimes the power cord must enter and exit through a single receptacle aperture, requiring the power cord to be pulled through, bent and pushed back through. While fit for their intended purposes, receptacles using the insulation displacement connection method provide less secure electrical connections than those that use terminal screws. In addition, insulation displacement connections can make rewiring a receptacle more difficult and can be prone to wire breakage as the cord must be unbent and bent during the rewiring process.
Prior art self-contained receptacles that do provide terminal screws for improved electrical connectivity provide but a single screw for connection of both entering and exiting hot wires, a single screw for both neutral wires and a single screw for both ground wires. Sharing a screw between entering and exiting wires can make receptacle wiring time-consuming, as both wires have to be arranged so that each has a good electrical connection.
Apart from electrical connection concerns, prior art self-contained receptacles can suffer from several other disadvantages. One common drawback pertains to the installation process. For example, the compact self-contained receptacle of Gesue, as disclosed in U.S. Pat. No. 7,394,019, comprises a cylindrical housing flush-mounted to a solid material wall or window sill. While the flush mounting can result in an aesthetically pleasing appearance, in many cases a user fails to achieve the desired look because receptacle installation requires a two-step hole to be drilled. A first diameter bore is to be formed to a shallow depth, then a second diameter bore, narrower than the first, must be made to a lower depth so that a cover plate can be seated in the counter sunk hole. Errors in drilling the larger hole can result in a cover plate that lies above or below the sill surface, rather than lying flush with the sill or wall. In addition to presenting a less attractive appearance, a cover plate seated below the surface can pose problems when an attempt is made to mate an electrical device with the receptacle. Furthermore, because the Gesue receptacle employs the insulation displacement connection method in which a cable must remain continuous when wired in a daisy-chain configuration a cable cannot be cut shorter to assist in pushing it back down the narrower hole, which can prove cumbersome or difficult for an installer.
Furthermore, prior art receptacles that use the insulation displacement method require a single cable to remain continuous throughout the circuit. These types of receptacles are often difficult or impossible to replace because the unbending and rebending of the cable during an attempted rewiring process can break the wires.
A further disadvantage of prior art receptacles is that in many cases they are configured for use with only non-metallic sheathed cable, and therefore cannot be used in applications in which metal-clad cable is used to provide power. Newer building code regulations that require the use of metal-clad cable can preclude the use of such receptacles, and therefore limit the wiring options available to the building user.
In addition, prior art devices often fail to provide features that can make the receptacle tamper-resistant. Consequently, they can pose potential hazards to consumers, and discourage those with young children from their use.